For more than a decade, the legal standard used to determine if you are driving drunk has been a 0.08 blood alcohol concentration (BAC). Of course, your impairment is not subject to such fine graduations. Some drivers may become impaired at lower levels and it is not as if at 0.07 BAC, you are perfectly sober and at 0.08 BAC, you become a sloppy drunk.
And while there has been progress in lowering the number of car accidents involving drunk drivers, there is still work to be done. In the 1980s, traffic deaths due to intoxicated drivers topped 20,000 per year. 30 years of improvements to vehicles and an aggressive campaign against drunk driving has brought that death toll down to about 10,000 annually.
The National Transportation Safety Board (NTSB) this week recommended that the legal BAC for all states be lowered to 0.05. They also proposed that all convictions for a DUI result in the installation of an ignition interlock, which forces drivers to supply breath samples when starting and driving a vehicle. If alcohol is detected, the interlock will not start the vehicle.
The lower standard would have a direct effect on how much patrons in restaurants and bars could consume before they would be legally drunk, and the American Beverage Institute strongly opposes the lower limit, describing it as "ludicrous," according to the New York Times.
The NTSB also supports the addition of built-in alcohol detection equipment in cars, which could measure BAC when the driver holds the steering wheel. This is likely to be highly controversial, especially if it became standard equipment on all vehicles.
Source: The New York Times, "Safety Board Considers Lowering of Legal Limit for Drunken Driving," Matthew L. Wald, May 14, 2013